Wednesday, September 24, 2014

Life in the multiverse means endless possibilities

What if...? Whether or not we live in the best of all possible
worlds, the multiverse can help us make the best decisions in this one

WE LIVE in the best of all possible worlds. So said Gottfried Leibniz in 1709.
For him, this was the only explanation for why a loving, all-powerful
and all-knowing god tolerated evil. Any attempt to improve our lot would
backfire, making it still worse. The world was not perfect, but
optimal; and Leibniz was its first optimist.

His argument did not go unchallenged. Voltaire parodied it through the character of Doctor Pangloss in Candide,
who clings to his Leibnizian optimism despite endless torments. But the
idea endured and evolved: "The optimist proclaims that we live in the
best of all possible worlds; and the pessimist fears this is true,"
wrote James Branch Cabell in 1926.

Now the question of possible worlds is
back on the agenda. Fifty years ago, Hugh Everett decided that the
neatest explanation for the oddities of quantum physics was that new
universes were continually being created – each slightly different from
our own. Many physicists now agree, with one even using it to again
address the problem of evil (see "Multiverse me: Should I care about my other selves?").

Popular culture, too, has embraced the
idea of parallel worlds, even if they are frequently depicted in ways
that depart considerably from Everett. There's obvious appeal in
what-ifs, and they aren't confined to science fiction: they feature in
everything from romcoms (Sliding Doors) to thrillers (Fatherland).